Cromwell and Alexandra firefighters have been using the stairs for the past two and a-half months as practice for the 51 flights of stairs they will encounter in the challenge.
Firefighters from Omakau, Frankton and Wanaka are among the 500 involved in the event, which raises funds for Leukaemia and Blood Cancer New Zealand.
On Saturday, Master Builders Central Otago sub-branch committee president Warren Whelan, of Alexandra, gave $5000 from the organisation to the cause.
''It's a very good charity and we're keen to help the firefighters on this because we have a very strong affinity with all of the brigades in the wider Central Otago region, including Queenstown, Frankton and Wanaka,'' Mr Whelan said at the Cromwell Fire Station.
''A lot of our staff are volunteer firefighters and, on occasion, some of our members have used the services of the brigades. We're aware of the amount of time our volunteer firefighters give to the community and we want to support them the best way we can, and this is one way for us to support them.
''The Leukaemia and Blood Cancer group is a charity that any one of us could require the services of in the future, so we see this as a win for us all,'' he said.
As well as raising money for a good cause, firefighters said ''bragging rights'' were at stake, with some gentle rivalry between the brigades during the challenge.
Dave Holden, of Cromwell, received a gold medal in the veterans age group last year and Alexandra firefighters Mark Hutton, Leon Burdett and Simon Smith received a silver medal in the teams contest in 2011, out of 21 brigades.
Firefighters compete in full uniform, wearing up to 25kg of kit, as they race up the Sky Tower.
Mr Hutton, Alexandra's deputy chief fire officer, said Central Otago brigades had traditionally been good supporters of the charity, thanks to the generosity of the wider community. Competitors had done everything from holding bingo nights to shovelling sheep manure to raise funds this year. This is the 11th year of the event and Adam Rubie, of Omakau, is competing for the ninth time.
''I've got an uncle who died of leukaemia, so that's my motivation,'' he said.
His training included bike rides up the Poolburn hill. Ardouin Baker, of Wanaka, said it was her third time in the challenge and she wanted to improve her previous times.
''It's a neat thing to be part of, with everyone cheering you on, and it's nice to be able to donate money to the cause as well.''
Last year's event raised a total of $319,000 for the charity.
